Hassan as a spawning ground for
the development of non-military
robotics and open source software.

He felt that the impact of
innovative ideas in robotics will, in
turn, provide opportunities for
return on investment of capital. He
brought Steve Cousins on board as
President and CEO, who helped
form WG into a model of
innovation incubation.

I have been favorably impressed
with Willow Garage since that first
visit, and briefly mentioned their
new experimenter’s platform robot
and ROS in last month’s column.
When the TurtleBot was introduced
this past summer, I felt that I just
had to look seriously at this
advanced experimenter’s platform that was significantly
cheaper than the PR2. In mid-August, I flew down to Willow
Garage in Menlo Park, CA and met with Melonee Wise and
Tully Foote — the co-developers of the TurtleBot. TurtleBot is
based on the iRobot Create — iRobot’s Roomba minus the
vacuum cleaner parts — and the Microsoft Kinect — the
vision game sensor for the Xbox 360. Having previously
seen many photos of the robot, I certainly wasn’t expecting
anything like the human-sized and very expensive PR2.
Though smaller than the PR2, the TurtleBot has capabilities
that I’ve rarely seen on any robot and certainly not one in
the range of $1,200 to $1,400 for a ‘ready-to-go’ machine.

Tully Foote, a Systems Engineer at WG, shown on the
left of the TurtleBot in Figure 4 and Melonee Wise, a
Senior Engineer at WG, shown on the right co-wrote the
initial proposal at Willow Garage, and then worked on the
development of the various hardware components and the
TurtleBot-specific software within ROS. It was to be an
internal WG project that utilized the just-released Kinect to
develop an entry-level mobile robot with many of the
capabilities of their PR2. The goal was to produce a mobile
robot with sufficient sensor/computing capability to perform
multi-robot research and demonstrate how a simple robot
design could take advantage of the many features of ROS.
They wanted an inexpensive robot that was easy to
assemble and was created from basic ‘off-the-shelf’
components. When visitors to WG saw the robots, they, of
course, wanted one, so WG polished the design a bit, and
now there are three vendors selling TurtleBots worldwide,
with dozens of schools and institutions using them.

All of these systems and components have been
available for over a year now and the TurtleBot is about as
straightforward as you can get for a basic robot design. There
is no cute little turtle shell body and there are no arms or
appendages of any sort, however, these and any other device
can easily be added at a later time. Experimenters can utilize the
basic intelligence instruction set of the Create, add an iRobot
Atmel ATMega 168-based command module (shown in Figure 5)

FIGURE 4. Tully Foote and
Melonee Wise with a TurtleBot.

Photo by Jimmy Sastra.

for the most basic routines, or use
the included powerful (for a
netbook) Asus 1215N to process
the Kinect’s vision and other data.

Key Parts of
the TurtleBot

Let’s look closer at the four key
components of the TurtleBot. The
robot uses the Create platform as
the base, power source, and for
motive power and steering. Kinect
serves as the main sensor suite and
does so quite well. Willow Garage
decided to use the Eee PC 1215N
netbook from Asus with 2 GB of
RAM and a 250 GB hard drive. This
netbook uses the Intel dual-core Atom
D525 processor that is powerful enough to handle the
demands of 3D data from the Kinect. For graphics, the Asus
uses the NVIDIA ION Discrete Graphics Processor. Also included
is a power and sensor board with an ADXRS613 single-axis
gyro that can measure the robot’s yaw rates up to 150
degrees/s. The board also provides regulated 12V power for
the Kinect (the USB cannot supply the required current) and
is mounted inside the Create. The rest of the components are
the four round mounting boards and the spacers for the boards
and Kinect mounting. The ROS software is provided on a
separate Flash drive and is also downloadable from ROS.com.

Basic Mechanical Construction

The four 12-3/8” mounting plates are perfect for
mounting experiments or even an inexpensive robotic arm.
The bottom plate is affixed to the Create and has a 5-1/2”
by 7-1/2” hole to allow access to the Create’s ‘cargo hold’
and interconnection of various cables. The front of the
lower plate is cut off to allow the Create’s homing sensor
to ‘see’ the charging beacon. The top plate is cut off at the
front so it doesn’t shadow the Kinect’s field of vision.
Originally, I had accidentally mounted the cut-off portion to
the rear (to line up the ROS/WG graphics) but found that it
affected the Kinect’s operation. You can easily do your own
modifications such as adding a bungee cord or long twist-tie to hold the netbook in place.

The bottom
three plates are
separated by two
sets of 2” spacers,
and the top plate is
separated by four
8” spacers. I also
tried removing one
of the 2” spacers
so I could swivel
the netbook in and